NEW YORK (Reuters Health) - Four melanoma peptides combined in an emulsion with granulocyte-macrophage colony stimulating factor (GM-CSF) yielded a stronger immune response in melanoma patients than the same peptide mixture pulsed on dendritic cells, according to the results of a 26-patient phase II trial conducted by researchers at the University of Virginia.
Results of the study, led by Dr. Craig Slingluff Jr., director of the Human Immune Therapy Center in Charlottesville, were published in the November 1st issue of the Journal of Clinical Oncology.
Patients in both groups received a tetanus helper peptide with the treatment mixture, as well as systemic, low-dose interleukin-2. Dr. Slingluff’s group developed the treatment mixture from four gp100 and tyrosinase peptides restricted by HLA-A1, HLA-A2, and HLA-A3. All patients enrolled in the study had stage III or IV melanoma.
After randomizing the patients to GM-CSF emulsion or dendritic cell delivery, each patient was immunized six times on days 0, 7, 14, 28, 35, and 42. The first three vaccinations were administered at two injection sites (primary and replicate), and the last three were delivered to the primary injection site only. At each injection site, half of the dose was administered subcutaneously and half intra-dermally.
For patients injected with the GM-CSF emulsion, T-cell responses to the melanoma peptide mixture were observed in 42% of peripheral-blood lymphocytes and 80% of sentinel immunized nodes. In patients vaccinated with the dendritic cells, the responses were only 11% and 13%, respectively.
Objective clinical responses were observed in two patients in the GM-CSF arm and one patient in the dendritic cell arm.
“Our results indicate the GM-CSF emulsion is most effective,” Dr. Slingluff said. “We expect to continue testing multipeptide vaccines with this emulsion.”
The GM-CSF arm of the melanoma trial remains open, and researchers have offered booster vaccines to patients who have demonstrated tumor regression or stable disease.
J Clin Oncol 21:4016-4026.
MeSH Headings:Clinical Trials: Environment and Public Health: Epidemiologic Methods: Evaluation Studies: Health: Health Occupations: Health Services Administration: Medicine: Investigative Techniques: Population Characteristics: Preventive Medicine: Public Health: Quality of Health Care: Recombinant Proteins: Specialties, Medical: Vaccines, Synthetic: Epidemiologic Study Characteristics: Clinical Trials, Phase II: Health Care Quality, Access, and Evaluation: Health Care Evaluation Mechanisms: Cancer Vaccines: Analytical, Diagnostic and Therapeutic Techniques and Equipment: Biological Sciences: Health CareCopyright © 2002 Reuters Limited. All rights reserved. Republication or redistribution of Reuters content, including by framing or similar means, is expressly prohibited without the prior written consent of Reuters. Reuters shall not be liable for any errors or delays in the content, or for any actions taken in reliance thereon. Reuters and the Reuters sphere logo are registered trademarks and trademarks of the Reuters group of companies around the world.
